The present invention relates to metal forming, and more particularly relates to forming a lump on the end of a metal pipe.
It is often required to form a part for a machine of the general form of a lump on the end of a rod. Nowadays it is becoming more and more common to use a hollow pipe instead of a solid bar. Conventionally, it has been practiced to form such a lump on the end of a pipe by making the lump separately and then attaching it to the end of the pipe by welding, melting together, or physical fastening such as screwing, interference-fitting or the like.
However, not only does this involve considerable labor, and considerable loss of working metal, but the final result is often of doubtful strength, since there is uncertainty as to the continuity of the connection.
Direct working of the end of the pipe by forging has been practiced; but this requires the end to be formed as a rough lump shape in advance.